Adjustable control ring



Nov. 20, 1956 D. M. ALLEGRETTI ET AL ADJUSTABLE CONTROL RING Filed Jan. 24, 1955 IN VEN TORS O/M/TE M. ALLEGRETT/ 400/5 A BY ATTORNEY ADJUSTABLE CONTROL RING Dante M. Allegretti and Louis P. Brunette, New Britain, Conn.

Application January 24, 1955, Serial No. 483,627

2 Claims. (Cl. 33-214) This invention relates to tools and instruments, and more particularly to an adjustable control ring especially adapted for use in adjusting the bubble tube of a level to any desired angle with respect to the straight edge of the level.

One object of the present invention is to provide a tool or instrument of the above nature, in which the adjustable control ring has a series of teeth on its periphery for selective engagement by the bit of a screwdriver located in a semicircular recess adjacent said ring for rotating it in either direction.

Another object is to provide a device of the above nature which will be simple in construction, inexpensive to manufacture, easy to install and manipulate, compact, ornamental in appearance, and very elficient and durable in use.

With these and other objects in view there has been illustrated on the accompanying drawing, one form in which the invention may conveniently be embodied in practice.

In the drawing,

Fig. 1 represents a side view of a carpenters square and level having the invention embodied therein.

Fig. 2 is an end view of the same.

Fig. 3 is a fragmentary view, on an enlarged scale, of a portion of the bottom leg of the carpenters square showing the clamping plate and the level adjusting ring in operating position with the bubble tube inclined at a declivity of 45 degrees.

Inited States Patent Fig. 4 is a fragmentary cross-sectional view on a still larger scale, taken along the line 4--4 of Fig. 3, looking in the direction of the arrows, and showing the tip of a Phillips type screwdriver in operating position in the semicircular recess for turning said ring in either direction to change the angle of the bubble tube.

Referring now to the drawing, in which like reference numerals denote corresponding parts throughout the several views, the numeral 10 indicates generally a carpenters square having an elongated leg 11 and a short base leg 12. Provision is also made of a pair of fiatsided mitre ribs 13 inclined at degrees from both of said legs 11, 12.

The short base leg 12 is provided with a level 14 including a curved bubble tube 17 mounted in a rotatable control ring 20. The elongated leg 11 has a pair of fixed levels 15 and 16 having bubble tubes 18, 19, which are permanently mounted in vertical and horizontal positions so as to serve as a plumb and a horizontal level respectively.

Provision is also made of a circular clamping plate 20a having a pair of opposed radial cars 23, 24 which are apertured to receive a pair of horizontal recessed headlocking screws 25, 26 of the Phillips, Allen, Reed and Prince or other similar type of screws for holding the clamping plate 20a in position above said control ring 20. Similar clamping plates 21 and 22 are located on the elongated leg 11 of said square.

The control ring 20 has a graduated scale 21a which is adapted to be viewed with reference to an index mark,

2,770,889 Patented Nov. 20, 1956 2111 on the adjoining short leg 12 of the square 10. In order to permit the adjustment of the control ring 20 to change the position of the bubble tube 17, provision is made on the exterior of said ring of a series of serrations or teeth 27 which are adapted to be located adjacent a semicircular recess 28 in the short leg 12 of the square 10.

The bottom of the recess 28 is provided with a small reduced conical socket 29 for receiving the tip of a. screwdriver 30 having serrated ribs 31.

Operation In operation, in order to unlock the control ring, it is merely necessary to insert the tip of the screwdriver 30 in the cross-shaped recesses of the heads of the two screws 25 and 26 to loosen them. This will also loosen the clamping plate 20a and permit the control ring 20 to be turned in either direction by inserting the serrated tip of the screwdriver 30 in the semicircular recess 28 with its point located in the bottom socket 29.

It will be understood that the teeth 27 on the control ring 20 are designed to fit the ribs 31 of the tip of the screwdriver 30, which ribs will also fit the recesses in the heads of thhe screws 25 and 26.

It will be understood that the present invention covers not only a tool having teeth on the exterior of a circular control ring, but also a circular control member having teeth located on its inside surface.

The invention may also be employed for adjusting a reciprocating rack having a straight row of teeth located adjacent a semicircular recess along the side of a tool or instrument.

While there has been disclosed in this specification one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not limited to the specific disclosure, but may be embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent is:

1. In a control member for a tool or other instrument, a circular ring having uniformly spaced teeth on the periphery thereof, a clamping plate overlying said ring and having a pair of radial cars which are recessed to receive headed screws for locking said ring to said tool or instrurnent in adjusted position, said tool having a recess adjacent said row of teeth, the bottom of said recess being provided with a reduced conical socket to guide the end of a screwdriver into engagementwith said teeth to permit the manual turning of said ring in either direction after said screws have been loosened. 2. In a builders tool comprising a combined square and level, an adjustable mounting for a bubble tube including a ring member having uniformly spaced teeth on the periphery thereof rotatably mounted on said tool, said tool being provided with a conically bottomed recess adjacent said peripheral teeth to guide the end of a screw driver for engagement with said peripheral teeth to rotate said ring member, and means to adjustably frictionally hold said ring member in a plurality of said rotated positions.

References Cited in the file of this patent UNITED STATES PATENTS 1,027,532 Finn May 28, 1912 1,920,892 Rogers Aug. 1, 1933 2,541,772 Lockard Feb. 13, 1951 

